In an age of corporate sponsorships, Tuesday is iTunes day. Apple has long claimed the day as its forum to introduce new musical additions to its iTunes catalog. Two weeks ago the day belonged to John Lennon. This week, it’s his former band mates, Paul McCartney and Ringo Starr. That overload of ex-Beatles is fueling a new round of thoughts on what is the most speculated of all iTunes mysteries: when will the Beatles and Apple Music take a bit out of iTunes and Apple Inc.

Theories are swirling. The latest buzz is saying maybe, September 5th will be that day. Apple has previously announced major product changes are on schedule for this quarter. The Beatles band members are getting increasingly frequent reference on Apple promotional materials (e.g. iTunes Tuesday). And now, Apple has scheduled a “Special Event” for the 5th and all reports are its iPod related.

Will it be the much speculated new square, widescreen iPod Nano? Possibly. It was two years ago to the exact week that the Nano was introduced. An upgrade on its birthday would make sense. Apple has also dumped inventory on some Nano’s over the sum. Nano? May be.

Could it alternatively be an evolution of the iPod Video? Possibly. Changes, including a rumored full screen model, are in the works and rumored from Asian manufacturers. Could it be the Beatles? Perhaps. Could it be all of the above? Sure. What will it be? No clue.

Like an Agatha Christy novel, Apple likes to spin its mysteries and that them brew a while before revealing the truth. Misdirection isn’t beyond their reach. They mystery captures minds, and captured minds open wallets. Apple is one of the best buzz marketers out there. As usual, they’re pulling all the strings of their machine.

I’ve guessed before, and guessed wrong, about a Beatles release (including a list of the top ten Beatles songs that could go with it) so in this, the 300th article on Metue, I’m hesitant to guess again. Most reports suggest that the Beatles are not coming until November, that the hold up is the digitization and remastering of catalog tracks. I’m inclined to believe that’s still “in the works” and this won’t be that announcement but anything is possible.

Apple will hold a joint U.S. and U.K. press event on September 5th. The image, copied here, used in the press invites to the event, shows a montage of cover art and the phrase “The Beat Goes On.” Are their hints in that? Perhaps. All of the album covers in the montage are modern and they span Genre’s. Beastie Boys, Keane, Mika, Jack Johnson (and two I can’t identify). A hidden message like an album played backwards? Maybe.

Fueling conspiracy theorists and hopefuls alike, Apple Insider has noted that the caption on the invite “the beat goes on” mirrors a line from the Beatles’ final press release from April 10, 1970, which said: “When the spinning stops — that’ll be the time to worry, not before. Until then, the Beatles are alive and well and the beat goes on, the beat goes on.” Coincidence? no way. Hint or misdirection? No idea.

Most likely Steve Jobs will stand up and reveal new iPods September 5th. Their shipping and availability, those will come sometime later…. And so too will the Beatles … most likely, possibly, perhaps … or perhaps not. In a few days we’ll know.

In other Apple news, the company has also just announced that episodes from 28 popular programs will be available for video downloads via iTunes in the UK.